1. Field of the Invention
This invention relates to a method for packaging a rolled web, wherein a wrapping material is wound around the outer circumferential portion of the rolled web which is to be packaged, and side edge parts of the wrapping material are folded onto opposed end faces of the rolled web which is to be packaged.
2. Description of the Prior Art
Methods for packaging a rolled web have heretofore been carried out wherein a wrapping material is wound around the outer circumferential portion of a rolled web which is to be packaged, and side edge parts of the wrapping material are folded in a chrysanthemum-like pattern onto outer end faces of the rolled web which is to be packaged. In general, such a method for packaging a rolled web is carried out with a mechanism Shown in FIGS. 6A and 6B. Specifically, as illustrated in FIG. 6A, a wrapping material 4, the width of which is larger than the width of a rolled web 2 to be packaged, is wound around the outer circumferential portion of the rolled web 2 to be packaged such that side edge parts 4a, 4a of the wrapping material 4 project beyond opposed end faces of the rolled web 2 to be packaged. Thereafter, as illustrated in FIG. 6B, each of the side edge parts 4a, 4a of the wrapping material 4, which project in cylindrical shapes outwardly from the opposed end faces of the rolled web 2 to be packaged, is folded by rotating the folding tools 10, 10, . . . centripetally from the side of the outer circumference of the side edge part 4a. The folds, which have thus been formed, are then pressed in the circumferential direction.
However, the aforesaid method for packaging a rolled web has the drawbacks described below.
(1) A number of folding tools must be used, which number is equal to the number of the folds, and therefore the packaging machine cannot be kept simple and cheap.
(2) The side edge parts of the wrapping material, which project in cylindrical shapes outwardly from the opposed end faces of the rolled web to be packaged, fall by gravity, and therefore appropriate folding operations cannot be carried out.
(3) The method for packaging a rolled web has little flexibility with respect to a change in the diameter of the rolled web to be packaged.
In order for the aforesaid drawbacks to be eliminated, novel methods for packaging a rolled web have been proposed in Japanese Unexamined Patent Publication Nos. 58(1983)-134824 and 58(1983)-134825. As illustrated in FIG. 7, with the proposed methods for packaging a rolled web, a wrapping material 4 having side edge parts 4a, 4a is used (only one of the side edge parts 4a, 4a is shown). Each side edge part 4a is folded into an L-shape from the middle part of the wrapping material 4. A leading edge part of the wrapping material 4 is brought onto part of the outer circumferential portion of the rolled web 2 to be packaged such that the bend corners of the wrapping material 4 are located at the opposed end faces of the outer circumferential portion of the rolled web 2 to be packaged. Thereafter, the rolled web 2 to be packaged is rotated such that the wrapping material 4 may be fed forwardly. In this manner, the wrapping material 4 is wound around the outer circumferential portion of the rolled web 2 to be packaged. A feed roller 20 and a folding roller 22 are located in the vicinity of each of the opposed end faces of the rolled web 2 to be packaged. When the wrapping material 4 is wound around the outer circumferential portion of the rolled web 2 to be packaged, each side edge part 4a is folded onto the opposed faces of the rolled web 2 to be packaged. In this manner, a plurality of folds of the side edge part 4a are formed one after another on each opposed end faces of the rolled web 2 to be packaged. Specifically, as illustrated in FIG. 7, with the proposed methods for packaging a rolled web, the feed roller 20 is rotated around an axis of rotation, which intersects perpendicularly to the direction along which the wrapping material 4 is fed. Also, the folding roller 22 is located on the side more forward than the feed roller 20 with respect to the direction along which the wrapping material 4 is fed. A slack portion, which occurs in the side edge part 4a having passed over the feed roller 20, is folded by the folding roller 22 onto the opposed end faces of the rolled web 2 to be packaged.
The methods for packaging a rolled web, which have been proposed in the aforesaid publications, can eliminate the drawbacks of the method for packaging a rolled web, which is illustrated in FIG. 6. However, the proposed methods for packaging a rolled web have the problems described below.
(1) The feed roller 20 is rotated around the axis of rotation, which intersects perpendicularly to the direction along which the wrapping material 4 is fed. Therefore, when the side edge part 4a, which has passed over the feed roller 20, is fed to the folding roller 22, the side edge part 4a has a velocity in the tangential direction of the rolled web 2 to be packaged. Accordingly, the wrapping material 4 cannot be folded appropriately by the folding roller 22 but becomes pushed outwardly in the radial direction of the rolled web 2 to be packaged (the outward direction is indicated by the arrow A in FIG. 7). Particularly, as shown in FIG. 7, with the method for packaging a rolled web, which has been proposed in Japanese Unexamined Patent Publication No. 58(1983)-134825, such that radial folds shown in FIG. 4B may be obtained, the axis of rotation of the folding roller 22 is inclined at a predetermined angle .delta. from the radial direction of the rolled web 2 to be packaged. In such cases, the wrapping material 4 markedly becomes pushed outwardly in the radial direction of the rolled web 2 to be packaged.
(2) Of the wrapping material 4, which has been folded onto the opposed end faces of the rolled web 2 to be packaged, the part forming a fold becomes thicker than the other part. Therefore, the part forming a fold cannot pass smoothly over the folding roller 22. As a result, a lag occurs with the formation of folds.
(3) The slack portion of the side edge part 4a, which portion has occurred between the feed roller 20 and the folding roller 22, cannot pass smoothly over the folding roller 22. Therefore, the sizes of the resulting folds and the intervals between the resulting folds fluctuate markedly.
In order to overcome the two problems described last to be eliminated, Japanese Unexamined Patent Publication No. 63(1988)-44415 discloses a means for forcibly passing the slack portion of the side edge part 4a over the folding roller 22. However, when such a means is employed, the folding speed cannot be kept high. Also, there is the risk that the wrapping material 4 is broken or damaged.